Welcome weeds: How alien invasion could save the Earth
20 January 2011 by Garry Hamilton
Taken from http://www.newscientist.com/article/mg2 ... ?full=true
Magazine issue 2795. For similar stories, visit the Endangered Species Topic Guide

Far from ravaging threatened ecosystems, non-native species could be powerful allies in the fight to save them.
WHEN Ariel Lugo takes visitors to the rainforests of Puerto Rico, he likes to play a little trick. First the veteran forest ecologist shows off the beautiful surroundings: the diversity of plant life on the forest floor; the densely packed trees merging into a canopy high overhead; the birds whose calls fill the lush habitat with sound. Only when his audience is suitably impressed does he reveal that they are actually in the midst of what many conservationists would dismiss as weeds - a ragtag collection of non-native species growing uncontrolled on land once used for agriculture.

His guests are almost always taken aback, and who wouldn't be? For years we have been told that invasive alien species are driving native ones to extinction and eroding the integrity of ancient ecosystems. The post-invasion world is supposed to be a bleak, biologically impoverished wasteland, not something you could mistake for untouched wilderness.

Lugo is one of a small but growing number of researchers who think much of what we have been told about non-native species is wrong. Aliens, they argue, are rarely as monstrous a threat as they have been painted. In fact, in a world that has been dramatically altered by human activity, many could be important allies in rebuilding healthy ecosystems. Given the chance, alien species may just save us from the worst consequences of our own destructive actions.

Many conservationists cringe at such talk. They view non-native species as ecological tumours, spreading uncontrollably at the expense of natives. To them the high rate of accidental introductions - hundreds of alien species are now well established in ecosystems from the Mediterranean Sea to Hawaii - is one of the biggest threats facing life on Earth. Mass extinction of native species is one fear. Another is the loss of what many regard as the keys to environmental health: the networks of relationships that exist between native species thanks to thousands or even millions of years of co-evolution.

Innocent as charged

Such concerns have fuelled an all-out war. Vast sums are being spent on campaigns to eradicate or control the spread of highly invasive exotics. Conservation groups enlist teams of volunteers to uproot garlic mustard from local parks. Government agencies fill waterways with poisonous chemicals to halt the advance of Asian carp. Most governments have no choice but to join the fight: under the terms of the Convention on Biological Diversity, signatory nations are required to do everything they can to eradicate or control the spread of threatening alien invaders.

Advocates for non-native species do not deny that they can sometimes create major problems, particularly in cases where disease-causing microbes are introduced into a new host population. But they argue that often the threat is overblown. For one thing, many species are not nearly as problematic as they are made out to be.

Take purple loosestrife, a Eurasian marshland plant frequently listed among the world's worst weeds and the target of multimillion-dollar eradication campaigns. It stands accused of destroying wetlands across North America, where it arrived more than 150 years ago, but there is as yet no documented evidence of any serious damage it has caused. Similarly, the notorious cane toad, introduced into Australia in the 1930s to control pests of the sugar-cane crop, is considered a major threat to the continent's unique fauna. Its highly toxic skin has long been seen as a death sentence for unsuspecting native predators, while its rapid spread is thought to have occurred at the expense of other amphibians. Yet the first serious impact study on cane toads recently concluded that they may in fact be innocent of all charges (New Scientist, 11 September 2010, p 18).

Even more surprising is the mounting evidence that many invaders are, in fact, good citizens in their new environments. Salt cedar - a group of Old World shrubs and trees belonging to the same family as the tamarisk - has been shown to provide valuable nesting habitats for birds in the arid American southwest. One of the beneficiaries is the south-western willow flycatcher, an endangered species at the centre of a 30-year, $127 million recovery project. Yet a costly programme to eradicate salt cedar is under way on the basis that it is using up valuable groundwater, though there is no proof that eliminating it will replenish water supplies.

In California, Australian eucalyptus trees provide a vital winter habitat for monarch butterflies, a species that has been in dramatic decline for decades due to deforestation in traditional overwintering grounds in places such as central Mexico. The widely loathed purple loosestrife, meanwhile, is favoured by bees, butterflies and waterfowl.

These are not isolated examples. In 2006, Laura Rodriguez at the University of California, Davis, published a study of the impact of non-native species. She found that they help natives in many environments and in a variety of ways: by providing new habitats and sources of food, by acting as hosts for organisms to live on and in, and by providing services such as pollination (Restoration Ecology, vol 17, p 177). Art Shapiro, also at UC Davis, has found that 40 per cent of native butterflies in Davis depend exclusively on non-native plants for their survival (BioScience, vol 54, p 182). In the marshlands of southern Spain, red swamp crayfish from the US have become a major food source for birds, otters, turtles and fish, including threatened species that breed and overwinter in the region (Conservation Biology, vol 25, p 1230).

There are other less conspicuous benefits. Only once conservationists had eliminated feral cats from Macquarie Island in the south-west Pacific did they realise that these non-native predators had become a vital link in the local food web. Since the last cat was killed in 2000, exploding rabbit populations have eaten much of the island's unique flora bare.

Anthony Ricciardi, a biologist at McGill University in Montreal, Canada, is not convinced by these examples. "The current rate of invasion has absolutely no analogue in the geological past. It's a massive experiment that's under way," he says. He argues that it is impossible to tell which invaders will be beneficial and which will be the next Nile perch, which is blamed for wiping out some 200 cichlid fish species in Lake Victoria in east Africa. "We still don't know what the full negative impact of invasive species is because most invasions aren't studied."

No mercy

For this reason, he and others conclude that all non-natives should be presumed guilty until proved innocent, with no expense spared to limit their spread. Even those who think such a view is too extreme admit that non-native species can cause major headaches. "There's no doubt there are massive problems associated with some invaders," says Andrew MacDougall, a plant ecologist at the University of Guelph in Canada.

Employing the precautionary principle may sound sensible, but if Lugo and other revisionists are correct, the indiscriminate eradication of aliens is not only unwarranted but could even have detrimental effects. In our fast-changing world, non-native species may be vital in maintaining ecosystem health. "A lot of the reason we've been afraid of exotics is because they are so well adapted for a lot of human-modified conditions and because they have been able to spread so rapidly," says Dov Sax at Brown University in Providence, Rhode Island. "But these are the same reasons why these species might provide benefits to humans in the future."

What happened in Puerto Rico offers a glimpse of how enemies may turn into allies. Once almost completely deforested, this Caribbean island has been the site of a large-scale, unplanned ecological experiment which began in the middle of the last century, when people began abandoning rural landholdings and moved to the cities. At first the results resembled a classic invasion storyline: much of the island was overrun by non-native weeds. However, the dominance of the invaders didn't last. As the decades passed, more and more species began taking root in the understorey. Some were aliens, but many - to the astonishment of observers, Lugo included - were scarce native species.

That's not all. When non-native plants were excluded from abandoned pastures, seeds of native pioneers - those that would normally be the first to colonise clearings - did not germinate. The problem was the harsh conditions of the altered habitat, including compacted soil, increased soil temperatures and reduced humidity in ground exposed to the sun, and the presence of ants with an appetite for seeds. Alien species such as the African tulip tree may have ameliorated the situation, improving soil quality as they grew. The non-natives would also have attracted birds and bats whose droppings would have contained viable seeds, including those of native plants. Similarly, the success of nitrogen-fixing exotic trees like white leadtree and white siris may have helped in places where nutrients had been depleted by human activity. "What's happened," says Lugo, "is the introduced species have somehow restored soil and canopy conditions."

Today, most of Puerto Rico's new forests support more tree species than its traditional forests, some by as much as 30 per cent. A long list of non-natives - including former plantation crops such as mango, grapefruit, banana, coffee and avocado - have become established in the wild, increasing the island's total tree species count from 547 to 770. What's more, the new forests seem as ecologically sound as the old ones. "We're starting to study nutrient cycling, water-use efficiencies, nutrient-use efficiencies and carbon sequestration, and we don't find much difference," says Lugo. The new forests "function beautifully", he adds.

At the very least the experience of Puerto Rico should reassure those who see all aliens as inevitably damaging. "This is not radioactive waste that's coming in," says Mark Davis, a plant ecologist at Macalester College in Saint Paul, Minnesota. "They're just species. If they're able to establish, then they'll have ecological functions just as native species will." It also suggests that invasion is part of a natural process of adaptation and reorganisation that is an unavoidable side effect of expanding human activity. "We've created completely new environments," says forest ecologist Jack Ewel at the University of Florida in Gainesville. "When you create a new physical environment, it's no surprise that a new suite of organisms proves to be better adapted to it than what was there before."

So how can we use these insights? Some conservationists are tentatively considering using non-native species to fill ecological niches left vacant by extinct natives. However, the complexity and uniqueness of ecosystems means such tinkering is a risky business.

Sax and Ewel acknowledge that the introduction of new species can backfire. But they want an end to an all-out war on alien species that increasingly seems misguided. For one thing, many campaigns against non-natives can themselves cause unwanted ecological surprises, not to mention a huge drain on resources. Fighting invasions with bulldozers and pesticides might also create just the right conditions for more invasions. And focusing on non-native species may divert attention away from more constructive conservation strategies, especially preserving native habitat conditions.

"There's been a big emphasis on looking at the negative side of the ledger when it comes to exotic species," says Sax. "But there are exotics that do a better job than natives of providing particular ecosystem services, and we need to start thinking more about the positive side if we're going to make informed decisions."

"In many cases, we're cutting ourselves off from a valuable ally," says Ewel. Lugo agrees. "Many of these invasions will probably have a pay-off in the future".

Invasive species: myth versus reality

They enjoy an unfair advantage
Several studies indicate that non-native and native species suffer comparable levels of predation and disease. Many highly invasive species only begin proliferating decades after they are introduced.

They establish permanent dominance
Alien species make headlines when they are at their worst, during the early stages of an invasion. What is rarely reported is that most of these population explosions are soon followed by equally steep declines.

They are a leading cause of extinction
There is no evidence of any plant species having died out as a result of non-native species arriving and the few such extinctions known to have occurred among animals have mostly involved new predators consuming prey with a limited range and nowhere to run.

They are a major threat to biodiversity
Ecosystems have been surprisingly adept at absorbing new species. Almost everywhere researchers have looked, overall species richness has risen due to non-native arrivals.

They are a huge drain on the economy
A widely quoted study concludes that damage from invasive species costs the US $137 billion each year (BioScience, vol 50, p 53). The study has been roundly criticised for ignoring major economic benefits and for including the cost of controlling species that may not need controlling, as well as factoring in events of questionable relevance, such as bird deaths caused by domestic cats.

Garry Hamilton is a freelance writer based in Seattle and the author of Super Species: The creatures that will dominate the planet (Firefly, 2010)

The following article is presented here with the kind permission of the author***.

It provides a powerful and well argued case that current and past NRM practices are still failing to halt the rate of degradation in the Australian landscape. We need to aggrade our land NOT continue to degrade. The article looks at the role of nativism in the current paradigm and offers real genuine options to our failing landscape.

Submission from Ben Gleeson* to SRCMA.

"G'day all,
Firstly, I'd like to say well done SRCMA for this consultation and forum initiative, perhaps this kind of thing should be a regular or ongoing occurrence; a bit like 'the conversation' but at a more local level. You could invite locals to post something stimulating occasionally and see if useful discussion resulted. Such discussion can get heated at times but that's generally just an indication that your forum is reflecting the diversity of our community.

Secondly, I’m sorry it’s so long and so late but it took me a while to compose these thoughts and I didn’t feel comfortable contributing something half-finished and clichéd or predictable. I do feel strongly about NRM and I’m not paid for my involvement so I can say what I see, just like any other ordinary member of the Southern Rivers community.

I'm not really sure where to put some of these comments but I'm going to choose this thread as the most appropriate. I have some concerns regarding our approaches to NRM and "the environment" which may be seen as criticisms but I hope no one will take these personally, they are more about the limitations of bureaucracy and cultural dispositions, and I know everyone (CMA and other forum participants) are working with good intent and to the best of their ability. Having said this, I doubt anyone would say we seem to be achieving ideal outcomes and ticking all the boxes, we all recognise there's room for improvement or we wouldn't be here on this forum.

I'll start out by suggesting that there is an intrinsic problem in the vision statement ‘Healthy landscapes, local people leading’, which is that the characteristics of the ‘healthy landscape’ are actually predefined by our government and NRM bureaucracy.

Not to put too fine a point on things but the ‘healthy landscape’ is generally measured by a very narrow set of outcomes, usually to do with how much native vegetation is present and how many introduced species have been eradicated (in support of this statement I’d say have a look at some of the NRM ‘outcomes’ statements you see floating around). Whether everyone accepts this point isn't important, the main thing I'm getting at is that the acceptable outcomes of 'local people leading' are basically already predefined for us by the accepted characteristics of a ‘healthy landscape’; local people may lead but they can only be encouraged to lead to a destination of healthy landscapes and the definition of ‘healthy landscape’ seems pretty clearly to be handed down from elsewhere. As such, we may well ask, is it really 'local people leading' or are we actually being led? Perhaps it is only selected local people, with the 'right' definition of a healthy landscape, who are allowed to lead?

I’ll say right here that I see far less of the approach I’m alluding to from within the SRCMA than elsewhere. I know from experience that the efforts being made to ‘walk the talk’ of engaging with community NRM values in this CMA are well ahead of those in many other catchments and I’m very grateful. I also know that the SRCMA is placed within a governmental hierarchy and is itself constrained by expectations coming down from above, so again I hope no one will take what I’m saying too personally. I just think that questioning the implicit expectations of the outcomes of ‘leadership from local people’ might show something about the situation we’re actually in here; and perhaps could explain why many people seem to feel that things are a bit stale in NRM-Landcare at the community level at present (witness the results from the recent National Landcare Facilitator surveys).

So what is the right definition of a healthy landscape? What do the NRM gods have in mind for us? Well from what I'm observing, it seems there’s an expectation that a healthy landscape is a more 'natural' landscape and that modified landscapes are necessarily less healthy. Furthermore, in Australia, in most officially sanctioned discourse and publications, we equate native vegetation and animals with 'healthy nature’ and non-native animals and veg with 'unhealthy, unnatural, humans’. A big part of the logic behind this is that, of course, humans are not natural.

This fundamental dualistic opposition between humans and nature (one defining the other, i.e. ‘nature equals not-human’ and ‘human equals not-nature’) is at the heart of so much of how we see ourselves and how we behave in relation to our environments. I don't wish to offend but you can clearly see the historical beliefs of religious-creationism supporting this perspective. It is strange to observe them still operating within NRM policy in this day and age. You'd have thought that the environmental sciences, which presumably guide our NRM activities, would have accepted Darwinian theories of evolution by now; but our fundamental connection to the rest of the biosphere (literally as a direct relation – as if by blood) seems to have been overlooked in favour of a perspective of dominion when it comes to managing “our” natural resources. The idea is that humans do not belong to nature; we are not part of natural systems, we just “live-off them” somehow (the connection is generally pretty vague).

I think if you look closely you can see correlations with the doctrine of terra nullius in operation here; a natural world devoid of humans.

I’m sure many folks don’t see terra nullius operating within NRM policy; but look at our (and most other westernised societies’) systems of national parks; a big area set aside for 'nature' which means ‘not human’ and therefore 'no people'. Well how does that actually work? How did we get to a situation where we think that the natural ecological communities of our continent should not be inhabited or affected by people? For the last 60,000 years people were a part of these ecological communities, I'd go as far as to say that we (I mean "we" Homo sapiens) have been a keystone species; managing and interacting with all parts of it to some degree. To withdraw humanity from a National Park and then claim that you've restored a ‘natural’ Australian system in some way is plainly unrealistic. It makes no sense at all unless, as I say, you are operating from a perspective that actually believes humans are not part of nature but were simply plonked down from somewhere else once upon a time.

The 'natural' systems that much of our NRM policy seems to be aimed at protecting or reinstating never existed without the presence of humanity; they were comprehensively adapted to and 'modified' by humans and I'd point out that they are now relatively unstable systems in the absence of these humans.

Having said this, it should be clear that these systems weren’t adapted just to ‘humanity’ per se; they were actually adapted to a particular human culture. Also, it must be clear that the natural system and the existing human culture (or rather multiple cultures across the whole continent) were co-evolved in direct relation to each other; culture was adapted to nature and nature to culture; this just had to be the case. The two were held in what is termed ‘a dynamic equilibrium’; not a static form of ‘climax’ stability but an ongoing, living, and vibrant process of continual mutual adjustment and constant change.

It is important that I acknowledge here that Aboriginal culture has undoubtedly survived Invasion. Aboriginal culture (or cultures) and Aboriginal connection to land continue and should be a source of pride for all who identify with these aspects of Australia’s long history of human occupation. I also want to make the point that Aboriginal culture today is a living and dynamic culture, not a ‘museum culture’.

Similarly, I’d suggest, it should be apparent that Australia’s ecological communities are a living and dynamic nature, not a ‘museum nature’. You won’t see living-nature in a museum; living-nature has already moved on; continually adapting and changing. This is true at many scales, from the cell, to the organism, to the population, to the community, up to the ecosystem and the biosphere as a whole.

Today, we have a culture in Australia that the pre-existing natural systems (pre-1788) were never adapted to. Yet because we maintain our peculiar belief that humans are not part of nature and that nature is extinguished by human culture and modification, we are in a very odd, almost psychotic, socio-ecological situation. One of the main reflections of this (the one most pertinent to this forum) is that although we have NRM policies which are guided by a drive to maintain a ‘healthy landscape’, it is a healthy landscape defined almost exclusively as the one which evolved in response to a previous culture; a culture which continues but which has also adapted and changed. Living-nature and living-culture have moved on but many of our efforts in NRM seem to be guided mainly by what we see in the terra nullius museum of nature.

I think this is a large part of why NRM agencies (and the Landcare movement) are failing to connect with so many commercial farmer-land-managers; they have at their core a vision of a healthy landscape which is inappropriate to the cultural realities of today. There is no point to (and really no hope of) reinstating a ‘natural’ ecological community which is closely adapted to a certain human culture after removing that culture and installing a different one. The system that you (we) are trying to install will require constant human management and interaction (because that's how it co-evolved) but the culturally defined incentives for appropriate management practices are gone; Australia has a different culture now.

If there is one clear and palpable example of the fact that we are connected as a natural part of this biosphere it is the food we eat to maintain our metabolic process. If humans were not a part of the natural world we could not live by digesting the material and converted solar energy made available to us by the other species that we consume; our metabolism just would not work. Once upon a time, Australians were nourished and sustained by their immediate natural environment; they moved through a healthy landscape literally as a part of it. Their connectivity to it was obvious and undeniable; their hunting, gathering and burning of the landscape shaped it and in return it shaped and nourished them.

As a contrast, consider our modern forms of ‘connection to nature’ as demonstrated by our actions in the NRM field. For example, today you can travel to any of our metropolitan centres (where the bulk of our population lives) and find various ‘care’ groups under the Landcare banner. The majority of these groups are almost exclusively focussed upon planting native species and eradicating non-natives as their contribution to supporting an idealised ‘natural’ world. Their efforts strangely ignore the fact that the ‘nature’ they are cultivating cannot provide them with their sustenance and so they must rely upon distant industrial monocultures and road transport for their nourishment. Where once there was a culture based on direct metabolic interaction with the rest of the natural system, now there is a culture sustained by the fridge and an ecological degradation taking place ‘out of sight and out of mind’, on distant farms which we frown about because we perceive that ‘they’ are somehow harming the ‘natural’ world.

It is our bizarre terra nullius museum version of ‘natural’ Australia that guides this urban goal to create a habitat of only concrete and native species; neither of which can sustain us. Because of our fallacious belief in the separation of nature and humanity we can live in a concrete jungle and deliberately cultivate a ‘natural world’ to which we have no metabolic connection. Like the ‘ghost in the machine’, we perceive ourselves as intellects without a physical grounding or direct connection to the biosphere; we seem to be above and beyond the material world somehow. Again this may be an indication of a cultural history of creationist perspectives. These are older perspectives, without grounding in evolution, ecology or science, yet the contradictions they engender within NRM activities and policies seem to pass unnoticed and unquestioned.

Because of our misplaced environmental intentions and our insistence that humans and nature are separate, we try to create what are inherently unstable ecological systems supported only by repeated inputs of fossil fuels (herbicides, chainsaws and bull-dozers), 1080, trapping and shooting, volunteer labour and taxpayer funding. These entirely unnatural systems are cultivated and maintained in complete disconnection to ‘living-nature’ and are open to continuing weed and pest invasions (naturally enough!) which are a reflection of the ecological vacuum we are attempting to install and maintain. The biological destruction implied by our ‘war on weeds’ is staggering, I’ve seen ‘CRC Weed Management Systems’ literature which states that 17% of all species in Australia are weeds. Is this an indication of how many of the Earth’s presently existing life forms we are ‘at war’ with? How much death and destruction are we prepared to inflict in defence of “our natural resources”? Who made us the natural world’s judge, jury and executioner?

I accept that many people feel that being surrounded by what they perceive to be ‘natural’ systems of native vegetation can be emotionally uplifting. However, we must question the validity of this emotional uplift in light of the fact that it relies on our terra nullius version of nature; a westernised cultural construction of an illusory separation between nature and humanity.

Recreational visits to national parks where we bring our own food and drink and shelter are not actually a way to connect with nature; they are like a package tour version of the natural world. Without a recognition and cultivation of our direct metabolic connection to nature we enter a national park like an astronaut in a space suit enters space; simple observers, floating by and then returning home. We are fools if we believe this is a true connection with ‘nature’. An ecological connection implies a shared metabolism not simply a one-way emotional connection to an abstracted and idealised mental construct; a perfectly imagined nature, perfectly separated from us.

As modern Australians we must admit that our real and direct connection to the rest of the biosphere can only come from our agricultural pursuits. In agricultural cultivation and food-gardening we should recognise our undeniable participation in the natural metabolic and ecological exchanges of the planetary biosphere. It is only within the process of consuming and being consumed that we have evolved as a co-adapted participant with the rest of the natural world.

However, the terra nullius museum often operates in our agricultural systems as well, although here it is oddly reversed. Instead of an absence of humanity, within modern conventional agriculture we tend to imagine a complete absence of nature. Again, because we see humans and nature as opposites and separate, we believe that human management within agricultural systems means that nature is somehow absented. Of course this is also complete nonsense; putting up a seven strand barb-wire fence doesn’t mean you’re now farming in a different universe; the natural world, with its inescapable ecological laws and processes, still applies. We seem to have come to a situation in agriculture where we think that we can go outside and create a ‘perfect’ farm just like the one on the blackboard; an imaginary land with no messy and inconvenient natural cycles or phenomena. During farm planning exercises we can mentally abstract or ignore everything that doesn’t belong in our idealised farm and this often leads us to go out into reality and try to subtract or ignore those aspects which do not conform to our planning. We expect to see fences and a crop species and we treat everything else as a weed to be removed. In this way we have actively simplified our landscapes; we employ a methodology of mental abstraction and the outcome is ecological simplification.

This is a reflection of a farming culture that is hostile towards living nature. It is just as opposed to an adaptive self-organising nature as is our NRM version of nature from the terra nullius museum. Both share hostility towards natural ecological responses, which are seen as ‘weeds’ to be combated. One approach sees these natural responses as impositions upon an imaginary ‘perfect farm’, the other sees them as sullying an imaginary ‘perfect nature’. In reality neither of these approaches is appropriate and both will inevitably achieve limited and unsustainable success in terms of landscape health. They both occur because of a simple (but ridiculous) imaginary separation and opposition between what is human and what is nature.

Farming as if in the absence of nature isn’t undesirable because it is hostile to a ‘perfect nature’ which needs protection from humanity, rather it is undesirable because it undermines landscape health and fertility; and hence farm productivity. Although it has been demonstrated that farming ‘in spite of’ nature (in artificially simplified systems, using pesticides and massive energy inputs) can raise the productivity of a narrow range of domesticated species, it has also been demonstrated that farm systems such as these are undermining the healthy functioning of the land. Simplified and abstracted systems of agricultural interaction with the natural world diminish the vitality of soils and regional water cycles. They undermine their own production in ways that increase vulnerability to a wide range of external shocks. Aside from this, they rely on the depletion of distant non-renewable resources as nutrient inputs to maintain their outputs, instead of building and maintaining the stored fertility of the local landscape.

Whilst ‘farming as if in the absence of nature’ is detrimental to landscape health, attempts to install an idealised ‘nature’ that exists in the absence of humanity and human culture are equally detrimental. We cannot solve our psychological disconnection from the natural world by promoting a disconnected version of nature from out of the terra nullius museum. Basically, ‘more gum trees’ just isn’t going to cut it, this is pretty obvious to most of us by now. No amount of enforcement or monetary incentives will ever succeed in creating a farming culture that is based on the cultivation of an assemblage of native Australian species.

We need a more wholistic approach to the complex crises we are facing. Using a model of ‘a socio-ecological system’ as a basis for our CAP planning process might be a start but it is pointless to incorporate this term into policy documents and then carry on just as before. Recognising the existence of a socio-ecological system implies an understanding of the continuum and the co-adaptation of culture and nature (‘socio’ and ‘eco’). This should instigate a profound shift in our personal experience of both culture and nature and in our NRM approaches to both. We cannot continue to maintain a culture which operates in hostility to the complexities of the natural world but neither can we continue to promote a nature which supposedly exists as separate to our interactions and influence. A form of cultivation (culture) which only works on paper and not in reality, and a form of nature which requires our absence, are equally flawed; neither can be relied upon as a scientific basis for sound NRM policy.

It is pretty clear that there is a tension in this country between the currently advertised goals of our NRM agencies and the bulk of large commercial farmers. It is also interesting to note the tension between many desirable NRM outcomes and a pointless and demonstrably ineffective insistence upon native species and a lack of non-natives as primary contributions to landscape health. Open-minded individuals ought to publicly acknowledge this more often. Clean water, revegetation, carbon sequestration, biodiversity, resilient landscapes, soil protection, soil creation, remediation of pollutants and production of clean air; none of these outcomes are the sole preserve of Australian natives. In fact, in many situations, most, if not all of them can be promoted more effectively and efficiently by non-natives. So why aren’t we using these species for productive and regenerative purposes?

Speaking personally, I’m a bit tired of reading that one advantage of planting native species is that they are better adapted to growing under Australian conditions than non-native species. If this were the case there would be no ‘weed problem’ (as some see it) to worry about; the natives would easily outcompete the non-natives and would inevitably flourish because the conditions would favour their survival. In reality, the fact is that what native species were primarily adapted to was the presence of a particular Aboriginal culture and continuing Aboriginal land-management practices.

NRM agencies and Landcare have done many great things but they have failed so far to win the hearts and minds of conventional farmers who are biggest land owners and managers in Australia today. I’d suggest that many of these farmers may well be convinced if only the NRM science behind the goal of healthy landscapes was not so obscured and diverted by an ideological obsession with the imposition of an invented imaginary ‘natural’ world based entirely on native species. Our culture and this version of the ‘natural’ world are not compatible because this vision of nature does not include us and does not promote our connection to the rest of the biosphere; in fact, it undermines this connection.

There has been a great deal of scientific research into the characteristics of traditional and modern agricultural ecologies. The field of “agroecology”, as it is known, has documented the benefits of designing and installing more complex agricultural systems which are based on observation of the function of managed and un-managed ecological communities. It is has been demonstrated that diverse agricultural systems can provide numerous benefits to farming enterprises in terms of productivity and also to the wider community in terms of landscape health. This kind of agroecological approach has been popularly documented within Permaculture literature (for example) and elsewhere but its application has been part of commonsense farming practice for millennia, all over the world. Practices such as: using legumes to support the growth of other crops; maintaining diverse forest systems for multiple products; production of useful plants, shellfish, eels, fish, and ducks within rice paddies and ponds; and using grazing animals to manage groundcovers in horticultural operations; none of these are new. Deliberately cultivated heterogeneous landscapes which include diverse patches of different agriculturally productive systems must be acknowledged as a potential way forward in sustainable farming and land management. A more diverse and healthy farming landscape could be comprised of an integrated mosaic of multi-species forestry, cropping, horticulture, and grazing but this isn’t the advice our farmers and Landcarers seem to be receiving from present systems of NRM support.

What about simply adding a windbreak of chestnuts or other productive trees beside your paddocks? What about a windbreak of apples, hazelnuts, feijoas and honey locust, or other perennial legume, as part of your grazing enterprise? What if someone wanted to plant 1000 Ha of rolling hills to a diverse forest of productive non-native species? This might sound like a healthy farming landscape to some of us, but what are the chances of receiving support from present NRM funding sources for any of the above improvements? Where is the pamphlet or other source of advice that promotes this kind of beneficial agroecology to farmers and land managers? You won’t get NRM funding or support to add productive diversity like this to your unhealthy farm landscape. However, if you wanted to plant some eucalypts somewhere or buy yourself some herbicide you’re in with a reasonable chance.

The great leap forward in Landcare began through an act of cooperation between the National Farmers Federation and the Conservation Council of Australia. This amalgam of farmland management and environmentalism would not have been so very dynamic if it had not been widely recognised as a vital step. Too many farms were suffering from generations of inappropriate management and too many catchments were manifesting landscape-scale symptoms of degradation (loss of soil and biodiversity, salinity, nutrient pollution, etc...). Combining our farmers’ hard work and drive to maintain the productivity of our landscapes with the ecological insights of the environmental sciences improved outcomes for Australian landscape health and for farm productivity.

However, as I see it, the problem in community NRM today (as evidenced by 79% of respondents to a recent national Landcare survey stating “Landcare is in need of reinvigoration”) is that the Landcare movement is only officially supported when it wants to plant natives, fence out stock, or kill ‘weeds’. I reckon that community-level NRM is completely overshadowed by the environmental science side of the original Landcare combination. Trained environmental scientists, whose expertise is in (so called) ‘natural’ ecology, are very typically constrained in their outlook by a self-perpetuating nativist ideology. The perspectives imparted throughout environmental training and within bureaucratised environmental literature are heavily weighted towards the terra nullius view of nature and have very little relevance to agricultural production, except when it will accommodate and promote native species. The only real overlap between this perspective and most conventional agricultural systems seems to be the desire to “combat” weeds; today and forevermore.

I know there is more going on at the grass-roots Landcare level, and I know many Landcare facilitators are supportive of sustainability-related initiatives like community gardens, farmers markets, composting, organic production, compost teas and all sorts of other complementary practices; but have a look at what is officially sanctioned at the higher levels of our NRM bureaucracies, none of these more inclusive socio-ecological approaches are present as yet.

Many Landcarers and would be Landcarers are interested in seeing broader approaches to NRM from our governments and our government agencies. The explosion of interest in the perspectives and practices associated with Peter Andrews and Natural Sequence Farming has been a clear indication of the latent desire, among many, to hear of new approaches to the health and productivity of their land. Most of these people are completely ordinary farmers and land holders who have not been entirely convinced by the standard recipes supplied by NRM agencies to date. What approaches like NSF and Permaculture have offered is an ecological perspective on agricultural management which is free from nativist shackles.

The desire to maintain non-native species like willows as part of our healthy agricultural landscapes is due to the fact that they actually work to stabilise and reverse unhealthy processes of degradation; and they do so in harmony with existing agricultural practices. NSF points out that if you’re farming in an unhealthy landscape the last thing you want to do is going around killing the only things that are managing to grow; we need to look at ways to work in cooperation with natural processes. This is true even if those natural processes manifest themselves as the growth of ‘weed’ species which aren’t in our terra nullius museum catalogue of the ‘natural’ world.

Now, I’m not saying our CAP should be aimed at eradicating native vegetation. What I’m saying is that landscape health can be promoted more effectively (beyond current ceilings) by abandoning a focus upon native vegetation as the only indicator of progress in landscape health. I’m also saying that farmers would do better if they adopted intelligent ways of increasing ecological complexity in their farming landscapes and they should not be compelled to use only native species to achieve this complexity. We don’t have to promote native species to incorporate and support the natural function, health and productivity of agricultural landscapes. In fact the opposite is true; we often undermine natural functions when we remove naturally occurring ‘weeds’ to maintain our ecologically unstable systems. Detrimental landscape outcomes will result whether we do this because we believe monocultural systems are more productive or because we are guided by a perverse ideological desire to impose a doctrine of ‘natural’ terra nullius.

In closing it seems all too obvious that NRM agencies should be enabled to strenuously promote agroecological approaches as a component of their mandate to improve landscape health at the catchment scale. So long as education and funding support are predominantly available only for the eradication of ‘weeds’ and the planting of native species, our NRM agencies will underperform and will inevitably fail us and all of our descendents on this continent.

***Ben Glesson is a Honours student at ANU, a father of two young children and a passionate Landcare member.

is the only real problem weed on my native pasture property in northern victoria. There are many other weed in small quantity spread throughout the pasture, they are seem to be controlled by the grass cover, stock (cattle) and the slashing as per Peter Andrews.

Bathurst burr is a summer weed and responds to small amounts of summer rain. The growth is not slowed by active summer C4 grasses or standing hay (dormant C3 winter grass).

I have not discovered why the burr grows so well but I'm looking for the best time to slash the weed to make use of its growth.

Bathurst burr is a summer weed and responds to small amounts of summer rain. The growth is not slowed by active summer C4 grasses or standing hay (dormant C3 winter grass).

I have not discovered why the burr grows so well but I'm looking for the best time to slash the weed to make use of its growth.

Part of the answer lies in your question

the burr grows so well

. Growth is a key factor here as the burr doubles it's mass every 10 days....that's a huge amount of productivity and take up of carbon. Let's do the numbers, Say after the first 10 days the burr weighs .5kg (inc roots). 10 days later 1kg, ten after that 2 kg, ten more 4 kg, and again 8 kg and after 60 days 16 kg !!! If they go to 70 days that's a massive 32 kgs.

They favor growing where the ground has been compacted esp by sheep and other hard hooved ungulates and like high nitrate conditions (animal dung and urine).

So the best time to slash is when they have finished growing to get the maximum benefit of the minerals their deep tap roots bring up and the increase in soil carbon and soil organic matter.....

My thinking thanks to Peters books is along the same lines but I'm still scared about the number of seeds on the mature plant being spread around.

Bathhurst burr over the previous two years did not grow very well, it was out competed by the summer grasses. The result was low levels of residue when slashed. This year conditions were suitable for the burr and away it went from the seed bank in the soil. I don't know how long the allelopathy effect lasts in the soil?

If I slash this years burrs the seed bank will again be huge, it may be next year or 5 years before the conditions are right to grow in mass again. Does anyone know if there is any info on how long the allelopathy effect lasts?

Hi All,
It is amazing how reading Peter's books and following NSF can change your view on many aspects of life.
I live in suburbia, and even my approach to growing vegies has changed. I let weeds proliferate in my patch and then chop them up and add all sorts of grass clippings, and find I can grow tomatoes on the same patch each year with great results.

I've just finished reading a book by Germaine Greer called " White Beech ". She bought a piece of land that was degraded rainforest in Southern Queensland, and set about replanting and regenerating the forest, where the canopy was mostly intact.
The book is a bit of a diatribe on how evil weeds are at times, which in a conservation context, I guess would be a management challenge. But even here there are clues given by the author, probably unintentionally, about the value of weeds...
"Every year we remove tons of Lantana with chainsaws and brush hooks. The soil where it grew is always clean, friable and cool, immediately ready to plant into...."